tl:dr; Same Estradiol test at LabCorp and Quest are wildly different.
I've been on TRT for a while now and am still having a hard time getting everything dialed in. I have other problems besides Testosterone though, so even if my Test and E2 are perfect I still won't feel great (low cortisol, thyroid, etc). I have a standing order to get my labs checked every so often, and usually get them done at LabCorp. A few weeks ago I thought I was having high E symptoms (Hard to maintain an erection, soft erections, nipples feel weird, etc) - but, for me, high E and low E feel pretty similar, so I wanted to get my levels checked before I changed anything again. Long story short, if I use my standing order it takes about 2 weeks for the results to show up in the online portal at LabCorp, so I paid out of pocket to get my Estradiol checked at Quest, so I could get the results in a few days. I also went to LabCorp right afterwards to get the full standing order for the rest of the results (Testosterone and DHT).
I just got my results back and it makes no sense - At approximately 7:30 AM I got my blood drawn at Quest. My results:
Estradiol, Ultrasensitive, LC/MS - 32 H - Range: <=29
Then, I immediately drove to LabCorp and got another draw at 8:12 AM. My results:
Estradiol, Sensitive (LC/MS/MS) - 20.9 - Range: 8-35
Since I got the results from Quest first I upped my AI a tiny bit, and maybe felt a little better (like I said, other issues keep my feeling pretty shitty no matter what my T and E2 are). But at LabCorp my Estradiol is almost perfect, maybe a tiny bit low. Like I said, high E and low E feel pretty similar to me, so I'm kind of at a loss as to what to do, or which lab to trust. I don't want to be too high, but I don't want to be too low long term either. Which test is more 'right'? How can you reconcile these two tests? Anyone had this happen before?